New Delhi: Prime Minister Narendra Modi on Saturday unveiled digital versions of at least 100 secret files relating to India's great freedom fighter Netaji Subhas Chandra Bose, whose death continues to be a mystery even after seven decades.

On the occasion of 119th birth anniversary of Bose, Modi launched a webportal https://netajipapers.gov.in, created for the public viewing of the files, at the National Archives of India.

"As a first step, the National Archives of India is placing 100 files relating to Netaji in public domain after preliminary conservation treatment and digitisation," the PMO said in a statement.

The remaining files will be put in the public domain after their digitisation, it added.

"The Government of India has written to the concerned foreign governments to declassify all files or papers related to Netaji. The government is committed to pursue this matter with them," it said.

Meanwhile, Netaji's family members were overwhelmed by the decision, calling it a "great day for the entire nation", IANS reported.

Modi also met family members of Netaji, including Professor Chitra Ghosh, Chandra Bose and Surya Kumar Bose.

Modi, in a meeting with members of Netaji's family in Delhi on October 14, 2015, had announced that the union government would declassify the files relating to Netaji in a phased manner, and make them accessible to the public.

Accordingly, the first lot of 33 files was declassified by the PMO and handed over to the National Archives of India on December 4, 2015.

"Subsequently, the ministries of home Affairs, and external affairs too initiated the process of declassification of files relating to Netaji Subhas Chandra Bose in their respective collection which were then transferred to the National Archives of India," the statement added.

Netaji, one of the leading lights of the Indian freedom struggle, set up the Indian National Army (INA) during World War II to take on the British Indian Army.

A former Congress president and once a close associate of Mahatma Gandhi, Bose's reported death in a plane crash in Formosa, now Taiwan, in 1945 has remained a mystery. The bespectacled freedom fighter was born on January 23, 1897 in Cuttack, Odisha.

The National Archives received 990 declassified files, pertaining to the INA, from the defence ministry in 1997.

West Bengal Chief Minister Mamata Banerjee demanded that Netaji should be declared "Leader of the Nation".

"Netaji Subhas Chandra Bose must be given the title 'Leader of the Nation'. He deserves that honour," Banerjee tweeted minutes after Modi declassified the files.

The Mamata Banerjee government on September 18, 2015 had released 64 files running into 12,744 pages in the presence of Netaji's family members, campaigning for declassification of the files to unravel the mystery surrounding his sudden disappearance over 70 years ago.

The release of the files "will meet the long-standing public demand" and "will also facilitate scholars to carry out further research on Netaji", a culture ministry statement has said.

Nobel Laureate Amartya Sen said in Kolkata on Saturday that he was interested in seeing the contents of the files. But it was far more important to debate his (Subhas Chandra Bose) life and work, to follow his vision, rather than to discuss in what circumstances he died.